Photographic image receiving sheet



Aug. 7, 1951 w. J. MCcuNE, JR

PHOTOGRAPHIC IMAGE RECEIVING SHEET Filed June 10, 1950 \NVENTOR) ATTORNEYS Patented Aug. 7, T7951 PHOTOGRAPHE() IMAGE RECEIVING SHEET William J. McCune, Jr., South Lincoln, Mass., as-

signor to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Application June 10, 1950, Serial No. 167,446

(Cl. S35-9) 6 Claims.

This invention relates to photography and more particularly is concerned with a photographic product for use in a photographic transfer process.

Objects of the present invention are to provide a sheet of image-receptive material for receiving a photographic transfer image and having means thereon which frame the image and which are bonded to said image-receiving sheet, and especially to provide framing means in the form of a mask which is secured to the image-receiving sheet by an improved strippable bond; to provide a stripping bond between an image-receptive material and a mask superposed thereon and comprising a coating of zein over the surface of the masking sheet adapted to be secured to the imagereceiving sheet and a coating comprising ethyl cellulose applied over said zein coating and adhered to the image-receiving sheet; and to provide products of the character described wherein said zein and ethyl cellulose adhesive coatings each includes an appropriate plasticizer and wherein said image-receptive material comprises barytaJ paper and the masking sheet comprises condenser or tissue paper.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the product possessing the features, properties and the relation of components which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a, fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in con,- nection with the accompanying drawings where- Figure v1 is a diagrammatic perspective view of one embodiment of the invention and illustrates the use thereof in conjunction with photosensitive sheet material;

Fig. 2 is a diagrammatic exaggerated sectional view along the line 2--2 of Fig. 1; and

Fig. 3 is a diagrammatic exaggerated sectional View similar to Fig. 2 wherein the operation of removing the processed transfer image is shown.

As it is understood to the art, a, photographic transfer process may be carried out to form in an image-receptive material a reverse image of a latent image contained in an exposed silver h alide photosensitive sheet material. By one practice, a transfer process may be effected by spreadmg a viscous liquid composition between and in contact with an image-receiving layer or sheet and an exposed silver halide photosensitive layer which are arranged in superposed relation. The processing compositionemployed is one which is capable of developing a latent image in the photosensitive layer and of providing an imagewise distribution of image-forming components therein as a result of said development. These imageforming components are transferred in solution, and without appreciably disturbing said imagewise distribution, from the photosensitive layer to the image-receiving material where they are reacted or developed to provide the desired reverse image.

In a practical embodiment of the invention, it is desirable to provide framing means in the form of a mask of a relatively thin flexible material on the surface of the image-receiving sheet or film which is adapted to receive the transfer image. This mask is provided with an aperture adapted to denne the picture area on the image-receptive material while the portions of the mask which surround the aperture restrict contact of the processing composition to the picture area and also confine the transfer image thereto. It is necessary to temporarily bond or adhere this mask to the surface of the image-receiving sheet so that the image-receiving sheet may be stripped from the mask in providing the finished positive print. At the same time the bond between the mask and the image-receiving sheet must have a suflicient strength to hold the mask on the sheet during handling, storage and use of the film.

rThe present invention is directed to these framing means in the form of a mask and to an improved bond for securing the mask to the imagereceiving sheet.

With reference to the drawings, Fig. 1 diagrammatically illustrates image-receptive material in the form of a flexible image-receiving sheet or layer or positive film l0 ready for processing in conjunction with an exposed silver halide photosensitive sheet material or negative lm I I which comprises an emulsion layer I'l carried on conventional film base l5. A picture frame portion of the negative lm Il is assumed to have been exposed to a subject in suitable camera apparatus and Fig. 1 includes a pair of pressure rolls 4!! used in camera apparatus for processing lms l0 and ll. Positive lm l0 and negative film Il, as shown, are in roll form although it will be appreciated that the invention may be carried out with cut lm or film packs. A camera for use with roll rllm of the type illustrated is described in United States Patent No. 2,455,111, issued to Joseph F.

' 3 Carbone and Murry N. Fairbank on November 30, 1948, for Self-developing Camera.

Roll film, such as that illustrated, has a, plurality of picture frame portions extending successively and substantially from end to end thereof. ture frame portion has a removable print section I2 lying Within the confines thereof and defined by perforations I4 which extend through the layer and which permit each removable print section to be removed from the image-receiving sheet.

To facilitate removal of each print section I2,Y

the image-receiving layer It provided with a tear-out or thumb hole It located adjacent theV leading edge of the removable print section, i. e., the transverse edge of a print section which first passes between the rolls it during processing. In the embodiment illustrated in Fig. l, perforations le are in the shape of curved lines adapted to provide a deckle and are arranged to enclose a rectangularly shaped area.Y Adjacent the leading transverse edge of the deckled portion,

In the image-receiving layer I0, each picstraight line perforations I8 areformed in the sheet I0 and extend from each corner of the deckle towards the tear-out hole I5. The thumb hole I and straight line perforations I8 are arranged and designed to assist removal of their associated print section I2.

Each removable print section I2 is adaptedto have a picture area which lies inside of the margins orboundaries thereof as defined by the perforations I4 and within which the transfer image is adapted Vto be confined. To provide this picture area, a mask or frame 2G of a iiexible sheet material, which has a length substantially equal to the image-receiving layer Il] and which is pro,-

Vvided'with an aperture for each removable print section of layer IQ, is superposed on the front or image-receiving surface of said layer with each aperture in registered relation to a print section I2 and is secured to the image-receiving layer It by a strippable bond. Apertures in the mask 2li, the edges of one of which are indicated in Fig. l Vby reference numeral 22,'are equal in number to the picture frame portions provided on the image-receiving sheet and extend'lengthwise of the masking sheet in spaced relation so that the apertures are separated center-to-center by a distance equal to the length of a picture frame portion. These apertures each have dimensions substantially equal to a picture area for the transfer image and consequently the edges 22 thereof will be within the boundaries It of each removable print section. Mask 2t has an overall Width slightly less than the width of the image-receiving sheet or layer It.

Freferred materials for the image-receiving Vlayer It and the mask 2t are, respectively, baryta paper and sulfate kraft condenser paper or tissue, the-latter having a thickness of from 0.001 inch to 0.003 inch. However, other flexible sheet materials may be employed and will be subsequently set forth.

As previously mentioned, the mask 26 is adapted to be bonded to the image-receiving layer Itl by a strippable bond, the reasons for which will hereinafter more fully appear. Image-receiving sheet I El and the mask 2Q are secured together by heat and/or pressure-sensitive adhesive coatings Vor layers 2d and 25 interposed therebetween. For use with a combination of baryta and condenser tissue, coating 2t is a plastic composition comprising zei-n and is applied onto the surface of the mask 2Q which isV located closestY tothe image-receiving sheet l,

,coating 2t and mask 20 and the bond between coating 26 and sheet IQ may be treated as substantially permanent bonds.

The combination of a subcoat 24 comprising zein and an overcoat 26 comprising ethyl cellulose has been found toV give a highly eflicient means for strippably securing the mask to the image-receiving layer It in that Vthis combination provides a substantially uniform bond over and between the contacting faces of these coatings. Consequently, the receiving sheet l0 and coating 26 permanently attached thereto may be evenly pulled away from the mask 2B and its permanently attached-coating 2t. 'At the same time, theV bond between coatings ZiV and 26 possesses sufficient strength to hold the mask 2i] flat and smooth on the surface of the image-receiving layer during rthe manufacture, storage and use of therproduct until the mask 29 and sheet It are to be separated.

The zein coating composition includes-an appropriate Zein solvent and a-suitable plasticizer'. One example of a solvent is isopropyl alcohol and water, while one example of a plasticiaer is triethylene glycol. Numerous solvents and plasticizers possessing the desired characteristics Yare known to the art and need no detailed discussion. A successful zein coating composition for Vcoat 2li contains about 10% solids in the solvent and about 10% of the solid content of the zein coat is plasticizer.

The coating 26 of ethyl cellulose is made up'of ethyl cellulose in an appropriate solvent to which a plasticizer is added. One example of a solvent for the ethyl cellulose is isopropyl acetate, while a plasticizer usable with the coating 26 is diethyl phthalate. Numerous solvents and plasticizers possessing the desired characteristics are known to the art and need no detailed discussion.V

A successful ethyl cellulose coating composition for the coat 26 contains about 10% solids in the solvent and about 20% of the solid content of this composition is plasticizer.

The ethyl cellulose coating 25 is applied directly over the zein coating 24 after the latter has thoroughly dried. Since it is practical to coat the mask 25! before vcutting the apertures therein, both coatings 24 and 26 may be applied Y,

by any conventional method. VA preferred practice is to apply coatings 24 and 26 by roll coating procedures. However, coats 24 and ZY may be applied by spreading the coatingV compositions over a surface ofthe mask with a doctor blade or by moving one surface of the mask in contact with a reservoir of coating composition or by immersing the mask in the composition. Y Appli- Y cation of the coatings 24 and 2t may be carried out at usually encounteredV room temperatures. Drying and curing of the coatings are facilitated by heat treatment and for this purpose the mask sheet, after the application of a coating thereon,

may be passed through a zone of air heated to aV Y temperature of about 200 F.

Variation inthe adhesion between the zein `coatZ!! andthe ethyl cellulose coat 2t is obtainable by variation in the quantity of plasticizer included in the zein coatingcomposition orby the addition thereto of an appropriate resin as well as by the inclusion of both of these materials in said composition. A suitable resin for this purpose is an aryl sulfonamide-formaldehyde resin of which that made by Monsanto Chemical Co. under the name of Santolite MHP is an example.

Following the coating operations and the formation of the masking apertures therein, mask Z is registered upon the image-receiving layer I and is sealed thereto by the application of heat and/or pressure. Preferably, this sealing is carried out by the use of a heated platen having a width dimension somewhat greater than the masking sheet and a length dimension approximating the length of a picture frame portion.

The image-receiving sheet with the mask superposed thereon in registered relation is placed upon a flat support and the heated platen is pressed onto the outer surface of the mask 2D. With a platen having dimensions of seven by three and nve-eighths inches, a total load of 400 pounds with a surface temperature for the platen of 140 C. has proved satisfactory for sealing the mask 20 to the image-receiving layer Ill. In instances where the image-receiving sheet Ill is of a length which includes a plurality of picture frame portions, the mask 20 may be successively registered with the successive picture frame portions of the image-receiving sheet ID and a heat sealing operation performed after each successive registration. Preferably, in order to facilitate removal of the print sections I2, the mask is allowed to remain unsealed over a small portion of the i image-receiving sheet in surrounding relation to the thumb hole I6.

A rupturable container 28, adapted to releasably hold a viscous liquid photographic processing composition, is associated with each picture frame portion of the positive nlm or image-receiving sheet I i3, and containers of this character are shown as mounted on the outer surface of the mask sheet 20 to extend transversely of the sheet It and mask 2D adjacent the leading edge of each picture frame portion thereof. These containers are made of a flexible, substantially liquid-impermeable sheet material which is folded over upon itself and sealed at its ends and along the adjacent long edges thereof which are brought togethei by folding. Complete sealing of the containers takes place after they are filled. Containers 28 are secured in their mounted position by suitable adhesive means. The long edge seal of each container forms the trailing edge and is designed so that when the image-receiving sheet facilitate understanding the invention and espe- I cially the manner in which the removable print section I2 is stripped from its bond with the mask 2U.

In the use of the novel product of the invention, the photosensitive emulsion Il of the nega- LlO tive film I I is suitably exposed in a camera. The exposed area of the photosensitive layer and a removable print section I2 of a picture frame portion of the positive nlm IIJ, which corresponds to the exposed picture frame portion of the negative nlm II, are simultaneously advanced as by pulling the ends of the films i and ll between the pressure rolls 4D. As a result, sufficient hydraulic pressure is created within the container, associated with said picture frame portion, by rolls 4D to rupture the long edge seal and forcibly discharge processing composition 29 from the trailing edge of the container. Continued movement of the two layers causes the released liquid to be spread in a uniform thin layer between and in contact with the image-receiving and the photosensitive sheet materials I0 and I I which are brought into superposed relation as they pass between rolls 4D. This layer of spread processing liquid 29 is shown in Fig. 3. Liquid spread outside of the picture area of th-e removable print section I2 is adapted to be trapped by appropriate trapping means (not shown).

Movement of the two sheets through the rolls 4Q is arrested after a picture frame portion has been pulled therethrough and the superposed sheets I0 and II in laminated condition, resulting from the action of the pressure rolls, are allowed to remain in the dark for about one minute. A door provided in the camera may then be opened and the processed print section can be removed by inserting a fingernail through the hole I6 and tearing the image-carrying layer along the perforations I8 and I 4.

It is to be particularly observed that the print section I2 is removed from the back surface of the image-receiving sheet IIJ, i. e., the surface most removed from the image-receiving face of the sheet I0. As the removable print section I2 is pulled away from the image-receiving sheet I 0 by breaking the unperforated marginal portions which join the marginal perforations thereof, stripping of the image-receiving layer from the mask occurs at the same time.

As may be seen in Fig. 3, that portion of the ethyl cellulose layer 26 which extends within the margins of the removable print section I'2 is stripped away from its adjacent zein coating 24. A portion of the ethyl cellulose 26 adheres to the removable print section I2 and forms a border for the positive image which is carried in or under the iilm formed by the liquid processing composition 29. Since the ethyl cellulose is substantially transparent, this border will remain substantially unobservable. It has been found that a combination of the zein and ethyl cellulose coatings 24 and 26 gives a remarkably clean separation between these coatings when a print section I2 is removed from the image-receiving sheet. This may be attributed to the uniform adhesion between the coats 24 and 26 and avoids tearing or other harmful effects to the removable print section, as well as to the remaining portions of the image-receiving sheet I 0.

It should be pointed out in connection with the diagrammatic representation of Fig. 3, that the layer of spread liquid, both during and after the photographic processing, dries rapidly to form a thin film. Thus, when imbibition time has been completed and the removable print section is ready to be pulled from the image-receiving Sheet Iii, the nlm formed by the spread liquid 29 is considerably thinner than shown, although it is usually not completely dry within a minute of spreading. Drying is completed by evaporation of agsesgss? which is exposed as a result of removal of the print section i2. The film formed by the spread liquid 29^is shown in Fig. 3 as'adhered to the image-receiving sheet ID and as beingremoved therewith when the image-receiving sheet is stripped from the composite nlm unit, although it Will be understood that the iilm formed by the spread liquid 29 may be caused to adhere to the emulsion layer Il Vof the negative photosensitive element Il when the image-receiving sheet is stripped from the composite lm.

As heretofore pointed out, the image-receiving sheet le may comprise any suitable image-receptive material. Arwide choice of materials is available fromthe fields of organic plastics, papers; reversible film-forming colloids, proteins such as gelatin'-l alhumen and the like and carbo hydrates s ch as starch and the like, as Well as mixtures of such materials where they` are compatible. Baryta paper, previously referred to, is a preferred material. It is to be noted that ethyl cellulose may he successfully bonded to any of the materials just mentioned as being suitable for use as the image-receiving sheet ifi.

With regard to the mask sheet 2li, any relatively thin material which may be secured to the image-receiving sheetV iii by a zein coating composition may be employed. As heretofore mentioned, a preferred material is condenser paper or tissue. As it is Well known to the art,y condenser tissue is a paper employed as insulation in the manufacture of electrical condensers. 1n addition, many other materials named as suitable for image-receptive layers, if made sufficiently thin, are usable Vfor the masking material 2G.

Since certain changes may be made in the above product without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.Y l

VWhat is claimed is:

1. A photographic product comprising an elongated iiexible image-receiving sheet material for use in a photographic transfer process as imagereceptive material for receiving a transfer image, an elongated iiexible sheet in superposed relation to a surface of said image-receiving sheet and providing a mask over portions of said imagereceiving sheet, said mask having at least one aperture therein which denes a picture area on said image-receiving sheet when said mask is superposed thereon, and two layers of adhesive interposed between said mask and said surface of said image-receiving sheet and bonding said mask and image-receiving sheet togeter, one layerV of adhesive comprising a coating of zein covering the surface of said mask which is closest to the image-receiving sheet when the image-receiving Ysheet and mask are in superposed relation and the second layer of adhesive comprising a coating of ethyl cellulose covering the surface of said layer of zein which is furthest removed from saidV Y mask, said layer of ethyl cellulose being adhered to said surface of said image-receiving sheet.V

A photographic product of the character defined in claim 1 wherein said image-receiving sheet and said mask both comprise paper.

3. In a positive film of the character defined in claim l, an image-receiving sheet which comprises baryta paper and a maskY which comprises tissue paper.

l. A photographic product of the character set forth in claim i wherein said Zein coating includes a plasticizer and said ethyl cellulose coating includes a plasticizer.

5. A photographic product of the character setV forth in claim 1 'wherein said coating of zein contains triethylene glycol as a plasticizer and said coating of ethyi celluose contains dlethyl phthalate as a plasticizer. Y

6. 1n a positive ilm of the character employed with a photographic transfer process wherein said nlm comprises an elongated flexible vimagereceiving vsheet material adapted to receive fa transfer image and a flexible sheet which pro=l vides a mask over portions of one surface or said image-receiving sheet and which is'arranged in superposed relation to said image-receiving sheet and bonded thereto and wherein said mask isV provided with at least one aperture which defines a picture area VVon said imagenreceiving sheet,

in combination, image-receiving sheet material comprising haryta paper and maskinfr sheet material comprising tissuepaper, and bond for securing said image-receiving sheet and said mask layer of adhesive comprising a coating of ethyl cellulose, plasticized with diethyl phthalate, and covering as an overcoat the surface of said layer of Zein which is furthest removed from said mask, said layer of ethyl cellulose being adhered to said image-receiving sheet. Y

WLLiAlVi J. MCCUNE, J

REFERENCES CITED The following references are of record in the Vfile of this patent:

UNITED STATES PATENTS Number Name Y Date 763,024 Schmid June 21, 1904 Y 1,212,447 Brown i Jan; 16, 1917 1,312,052 VSartorius Aug. 5, 1919 2,136,176 Hammond Nov. 8, 1938 

1. A PHOTOGRAPHIC PRODUCT COMPRISING AN ELONGATED FLEXIBLE IMAGE-RECEIVING SHEET MATERIAL FOR USE IN A PHOTOGRAPHIC TRANSFER PROCESS AS IMAGERECEPTIVE MATERIAL FOR RECEIVING A TRANSFER IMAGE, AN ELONGATED FLEXIBLE SHEET IN SUPERPOSED RELATION TO A SURFACE OF SAID IMAGE-RECEIVING SHEET AND PROVIDING A MASK OVER PORTIONS OF SAID IMAGERECEIVING SHEET, SAID MASK HAVING AT LEAST ONE APERTURE THEREIN WHICH DEFINES A PICTURE AREA ON SAID IMAGE-RECEIVING SHEET WHEN SAID MASK IS SUPERPOSED THEREON, AND TWO LAYERS OF ADHESIVE INTERPOSED BETWEEN SAID MASK AND SAID SURFACE OF SAID IMAGE-RECEIVING SHEET AND BONDING SAID MASK AND IMAGE-RECEIVING SHEET TOGETER, ONE LAYER OF ADHESIVE COMPRISING A COATING OF ZEIN COVERING THE SURFACE OF SAID MASK WHICH IS CLOSEST TO THE IMAGE-RECEIVING SHEET WHEN THE IMAGE-RECEIVING SHEET AND MASK ARE IN SUPERPOSED RELATION AND THE SECOND LAYER OF ADHESIVE COMPRISING A COATING OF ETHYL CELLULOSE COVERING THE SURFACE OF SAID LAYER OF ZEIN WHICH IS FURTHEST REMOVED FROM SAID MASK, SAID LAYER OF ETHYL CELLULOSE BEING ADHERED TO SAID SURFACE OF SAID IMAGE-RECEIVING SHEET. 